Planting with a Purpose: How Tree Planting Programs Can Support Green Infrastructure

Large-scale corporate tree planting pledges sound impressive on paper, but the results can be mixed at best, especially in terms of biodiversity conservation and carbon sequestration. A more holistic strategy involves pursuing projects that provide clear environmental and community outcomes, as illustrated by a new study that measures the value of mangrove trees for flood control.

Trees with purpose: The value of mangroves

The new mangrove study was produced by researchers from the Center for Coastal Climate Resilience at the University of California, Santa Cruz. The high profile study is featured in a recent World Bank report.

The researchers analyzed mangrove forests covering 700,000 kilometers, or almost 435,000 miles, of subtropical coastline in 121 countries. They concluded that mangroves provide valuable flood protection services to communities around the world, estimated at $855 billion over a 100-year period.

Much of the benefit accrues to countries with longer coastlines, including the United States, Australia, China, India and Vietnam. “As climate change accelerates the frequency and severity of storms, the need for effective coastal defenses has become increasingly urgent,” wrote University of California, Santa Cruz, reporter Mike Peña. “Traditionally, governments have turned to hard infrastructure like seawalls and levees to guard against floods. However, the center’s study reveals that natural ecosystems — particularly mangroves — can be equally, if not more, effective as coastal defenses, while providing additional environmental benefits.”

The ability of mangroves to provide flood protection is also illustrated by a study of the impacts of recent storms on Florida communities. “In Collier County, mangroves reduced annual flood risk by 25.5 percent to properties behind them. Many areas in the county received over $1 million in benefits every year in flood damage reduction benefits due to the mangroves in front of them,” according to the study. Even modest coverage by mangroves made a significant difference.

“The value of mangrove forests during Hurricane Irma was also very high,” according to the study. “Mangroves averted $1.5 billion in storm damages, amounting to a 25 percent savings in counties that have mangroves. They also protected more than 626,000 people across Florida.”

Preserving green infrastructure

The University of California study also revealed some insights into mangrove loss due to coastal development, shrimp farming and other activities. Fortunately, the rate of loss slowed to a crawl in recent years, at just 0.66 percent between 2010 and 2020. But the remaining mangroves are more important now than ever before. Given the rise of coastal populations, mangroves protected 61 percent more people in 2020 than they did in 2010.

“As governments and policymakers look to the future, the study provides a compelling case for investing in the conservation and restoration of mangroves,” Peña wrote.

There are many opportunities for the business community to lend a hand, too. In the U.S., for example, Florida established protective measures under the 1996 Mangrove Trimming and Preservation Act. But in some areas significant loss has already occurred. Tampa Bay has already lost nearly 50 percent of its mangroves over the past 100 years, according to the World Wildlife Fund. And the Charlotte Harbor estuary has lost almost 60 percent, contributing to stress on the manatee population among other impacts.

Stemming further losses and restoring some of these areas is a task already underway among non-government organizations like the Sanibel-Captiva Conservation Foundation, which manages more than 2,100 acres on Sanibel Island and surrounding areas, including South Fort Myers and Cape Coral. The nonprofit sponsors mangrove restoration projects along with educational programs and an “adopt a mangrove” program that enables residents to care for young potted plants at home until they are large enough to transplant.

Another organization, the Conservancy of Southwest Florida, monitors at-risk mangrove forests in several key areas, including the Clam Bay estuary. Despite significant damage from Hurricane Irma in 2017, “the ability of mangroves to bounce back from the brink of annihilation is phenomenal," according to the conservancy. “Given the chance and the right set of hydrologic conditions and circumstances, this system could rebound." 

On the education side, the university-based program Florida Sea Grant raises awareness about the importance of mangrove conservation.

“The complex root system of mangrove filters through pollutants and the tree captures more carbon than seagrass and even rainforests, overall improving water quality,” according to the organization. “Mangroves also provide an amazing habitat and food web for bird species, terrapins, invertebrates and fish.”

Grassroots activism is also building. The newly formed Jupiter Narrows Conservation Alliance, for example, is dedicated to protecting local ecosystems and fisheries threatened by development and other human activities. The organization aims "to preserve the environmental integrity of Jupiter and mitigate these impacts by protecting and restoring the Jupiter Narrows and its mangrove habitat and surrounding seagrass beds." 

The effort recently received a grant of $175,000 from the Florida-based Andrew Red Harris Foundation, which launched in 2014 with a reef restoration mission. The grant will enable the Jupiter Alliance, in partnership with the Ocean Conservancy, to move forward with a restoration plan for three mangrove islands that are severely degraded.

The mangrove restoration effort in Florida has many moving parts, providing businesses with new opportunities to partner with grassroots organizations and established conservation programs. New research also shows that trees in general are more efficient at carbon sequestration than previously known. By engaging with high-impact programs like mangrove conservation, business leaders can avoid some of the pitfalls that befall some corporate tree planting programs and focus on biodiversity-centered efforts that really make a difference.